This invention relates, in general, to a system and method for maintaining interactive services to a radiotelephone as it transverses a network of wireless systems and is particularly, but not exclusively, applicable to a digital cordless telephone system or wireless local area network (LAN) environment that supports data services in addition to standard telephony services.
The structure of modern telecommunication systems allows the routing of information such as encoded speech and data, to various forms of communication device. For example, cellular radiotelephones within a cellular service area may communicate with other cellular radiotelephones, landline telephones (via a public switched telephone network, PSTN), or interactive Internet service providers. In addition, there are data services which can be made available to cellular radiotelephone users, such as small message services (SMS).
Interactive data services which require a communication path directly to an application server may currently only be accessed by a radiotelephone located within its home site (where a site is a predetermined geographical area such as a building); this being the case for wireless LAN and digital European Cordless Telephone (DECT)-type systems. However, the primary benefit of a radiotelephone is the mobility it allows its user, but such mobility between sites compromises the ability of the radiotelephone to maintain a consistent level and breadth of interactive and data services (as opposed to voice-only services).
The position concerning the provision of services in a radiotelephone environment can be compared with conventional cellular services, such as the Global System for Mobile (GSM) communication. In GSM, services are generally restricted to those provided by the local service provider, with information transfer between a home location register (HLR) and visiting location register (VLR) restricted to management information to support roaming. In other words, a visited site may contain an inferior service set and so a roaming mobile subscriber unit is potentially restricted in its network interactions, with all such interactions effectively managed from the visited site.
According to a first aspect of the present invention there is provided a method of managing a data session between a communication device and an application server of a communication network containing at least two coverage areas each having base site equipment supporting a plurality of data services, the method comprising: affiliating the communication device with one of the coverage areas, thereby identifying that coverage area as a home coverage area and wherein the application server provides a predetermined set of data services thereto; during one of at least communication device registration with the communication network and data call set-up, determining whether the communication device is in its home coverage area; and when the communication device is in a coverage area other than its home coverage area, establishing a communication path through the communication network between the application server and the base site equipment providing service to the communication device, thereby remotely to offer the communication device the predetermined set of data services of its home coverage area.
In a preferred embodiment, the predetermined set of data services augment data services offered in said coverage area other than the home coverage area.
In a second aspect of the present invention there is provided a communication system having at least two coverage areas supporting differing data service sets, the at least two coverage areas each having base site equipment supporting data services from dedicated application servers, the communication system containing: means for determining whether a communication device is in its home coverage area; means for establishing a communication path through the communication network between first base site equipment providing service to the communication device and an application server of a home coverage area associated with second base site equipment, the communication path providing a service conduit through which at least one of a set of data services associated with the application server of the home coverage area is supplied to the first base site equipment, thereby remotely to support the communication device serviced by the first base site equipment with the at least one of the set of data services of its home coverage area.
The base site equipment may comprise a private branch exchange coupled to a router, whereby the communication path is established by the router in response to the address. Indeed, the base site equipment may include a DECT or wireless LAN interface.
In a further aspect of the present invention there is provided a method of managing a data session between a radio communication device and an application server having an identity, the application server coupled through a network to home base site equipment serving a first coverage area and second base site equipment serving a second coverage area, the method comprising: establishing the identity of a home application server associated with the communication device; routing the data session from the home application server via the home base site equipment when the radio communication device is in the first coverage area; and routing the data session from the home application server via the second base site when the radio communication device is in the second coverage area.
In another aspect of the present invention there is provided a computer program product for controlling routing of a data session between a communication device and an associated home application server providing a predetermined set of services in a home coverage area, the computer program product comprising: code that directs the router to determine whether the communication device is in the home coverage area; code that directs base site equipment, remote from the home coverage area, servicing the communication device to establish a communication path through a communication network to the home application server, thereby remotely to offer the communication device at least some of the predetermined set of data services of its home coverage area; wherein the codes reside in a computer readable medium.
Advantageously, the present invention allows a mobile conveniently to access its default set of service facilities (as well as any local data services supported by a serving PBX and associated server and in addition to a basic telephony facility subscriber unit), when the subscriber has roamed and is not therefore located within its home site. Provided that the subscriber unit includes a suitable man-machine interface (MMI), such as a character-based display capability, data services provided by a home application server may be accessed in visited sites (i.e. areas which are not the home site for a particular subscriber unit).